A variety of medical devices for delivering a therapy and/or monitoring a physiological condition have been used clinically or proposed for clinical use in patients. Examples include medical device that delivery therapy and/or monitor conditions associated with the heart, muscle, nerve, brain, stomach, or other organs or issues. Some therapies include the delivery of electrical signals, e.g., stimulation, to such organs or tissues. Some medical devices may employ one or more elongated electrical leads carrying electrodes for delivery of therapeutic electrical stimulation to such organs or tissues. In some examples, a lead may include electrodes that sense intrinsic electrical signals within the patient and/or other sensors for sensing physiological parameters of a patient. Other medical devices do not include leads, and instead include electrodes and/or sensors formed on or located within a housing of the device. In some examples, the medical device may be an implantable medical device (IMD).
Patients requiring delivery of electrical stimulation may also require other therapeutic or diagnostic devices or procedures. In some examples, such as the use of magnetic resonance imaging (MRI), the application of a defibrillation pulse, or the use of cauterizing equipment during surgical procedures, there is a risk of damage to circuitry within an IMD due to the additional therapeutic or diagnostic devices or procedures. In particular, the additional therapeutic or diagnostic procedure may generate large amount of electrical current that can cause damage to circuitry within the IMD.